TW202228159A - Anisotropic conductive film, connection structure and method for producing the connection structure - Google Patents

Abstract

An anisotropic electroconductive film having a structure in which high-hardness electrically conductive particles 1A having a 20% compressive elastic modulus of 8,000-28,000 N/mm2 and low-hardness electrically conductive particles 1B having a 20% compressive elastic modulus lower than that of the high-hardness electrically conductive particles 1A are dispersed in an insulating resin layer 2 as electrically conductive particles. The number density of the electrically conductive particles overall is 6,000 particles/mm2 or greater, and the number density of the low-hardness electrically conductive particles 1B is at least 10% of that of the electrically conductive particles overall.

Description

Anisotropic conductive film, connection structure, and method for producing connection structure

The present invention relates to an anisotropic conductive film.

For mounting of electronic components such as IC chips, anisotropic conductive films in which conductive particles are dispersed in an insulating resin layer are widely used. However, when an oxide film is formed on the surface of the terminal of the electronic component connected by the anisotropic conductive film, the connection resistance becomes high. On the other hand, it has been proposed to reduce the resistance by piercing the oxide film by using conductive particles with different particle sizes (Patent Document 1), or by using relatively hard conductive particles so that the conductive particles are immersed in the wiring to increase the resistance. The connection area can be reduced to reduce the resistance (Patent Document 2). prior art literature Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2013-182823 Patent Document 2: Japanese Patent Laid-Open No. 2012-164454

[The problem to be solved by the invention]

When conductive particles having different particle diameters are used as described in Patent Document 1, particles smaller than particles having larger particle diameters are immersed in the terminal, thereby making it difficult to sufficiently reduce resistance. In addition, if hard conductive particles are used as described in Patent Document 2, it is necessary to press-bond under high pressure during anisotropic conductive connection, and there is a connection structure between a substrate and an IC chip obtained by anisotropic conductive connection Deformation or cracking of the body.

In order to prevent the occurrence of deformation or cracks, there is a method to reduce the conductive particles. However, if the conductive particles are reduced, the number of conductive particles captured in the terminal will decrease, and the resistance will increase, or the on-resistance after connection will increase.

In this regard, the object of the present invention is to use high-hardness conductive particles so that the terminals can be connected even if the oxide film is formed, and to realize crimping under low pressure conditions, and to easily confirm the capture of the conductive particles in the terminals, The resistance reduction is surely realized. [Technical means to solve the problem]

The inventors of the present invention came to the present invention by finding that, when conductive particles having different hardnesses are mixed and used, the contact pressure is concentrated on the high-hardness conductive particles during anisotropic conductive connection, and the high-hardness conductive particles puncture and oxidize Coating; low-hardness conductive particles use "cracks formed by high-hardness conductive particles in the oxide film" to facilitate conduction; therefore, even if the particle density of high-hardness conductive particles is reduced, both high-hardness conductive particles and low-hardness conductive particles are also Contributes to the conduction of the terminal, so it can reduce the on-resistance; in addition, it can reduce the particle density of the high-hardness conductive particles, so there is no need for crimping under high pressure during anisotropic conductive connections, which can eliminate the deformation or cracking of the connection structure Furthermore, by mixing high-hardness conductive particles and low-hardness conductive particles, it is easy to observe the indentation of the conductive particles.

That is, the present invention provides an anisotropic conductive film in which high-hardness conductive particles having a 20% compressive elastic modulus of 8,000 to 28,000 N/mm ² as conductive particles and a low 20% compressive elastic modulus are dispersed in an insulating resin layer. In the low-hardness conductive particles of the high-hardness conductive particles, the number density of the entire conductive particles is 6000/mm ² or more, and the number density of the low-hardness conductive particles is more than 10% of the entire conductive particles. [Effect of invention]

According to the anisotropic conductive film of the present invention, even if an oxide film is formed on the surface of the terminal of an electronic component, the high-hardness conductive particles are immersed in the oxide film, and the cracks formed by the high-hardness conductive particles in the oxide film are utilized. , Low hardness conductive particles also contribute to the conduction of the terminal, thus reducing the on-resistance.

In addition, by mixing the high-hardness conductive particles with the low-hardness conductive particles, the crimping force required for anisotropic conductive connection can be reduced compared to the case where the conductive particles are composed of only the high-hardness conductive particles. Therefore, it is possible to prevent deformation or cracking of the connection structure of the anisotropic conductive connection.

Furthermore, in the connection structure through anisotropic conductive connection, the indentation of high-hardness conductive particles and the indentation of low-hardness conductive particles can be observed, especially the indentation of high-hardness conductive particles can be clearly observed. Accurately evaluate the number of trapped conductive particles in the terminal. Therefore, the reduction in resistance can be surely achieved.

Hereinafter, the anisotropic conductive film of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code|symbol represents the same or equivalent component.

<Overall structure of anisotropic conductive film> 1A is a plan view illustrating the arrangement of conductive particles 1A and 1B in an anisotropic conductive film 10A according to an embodiment of the present invention. 1B is an x-x cross-sectional view of the anisotropic conductive film 10A.

The anisotropic conductive film 10A is formed of a conductive particle dispersion layer 3 which is made of high-hardness conductive particles 1A with a 20% compressive elastic modulus of 8,000 to 28,000 N/mm ² and a low 20% compressive elastic modulus Both the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are dispersed in the insulating resin layer 2 . The number density of the conductive particles combined with the high-hardness conductive particles 1A and the low-hardness conductive particles 1B is more than 6000/mm ² , and the number density of the low-hardness conductive particles 1B accounts for more than 10% of the total conductive particles. The conductive particles are arranged in a square lattice as a whole, but there is no regularity as to which of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B exist at each lattice point.

<Electroconductive Particles> Both the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are present as conductive particles in the conductive particle dispersion layer 3 . Among them, the 20% compressive elastic modulus of the high-hardness conductive particles 1A is 8,000 to 28,000 N/mm ² .

Here, the 20% compressive elastic modulus is used to measure "the compressive variation of the conductive particles when a compressive load is applied to the conductive particles using a micro-compression tester (for example, Fischerscope H-100 manufactured by Fischer Instruments)", using the following formula. Calculated K value: 20% compressive elastic modulus (K) (N/mm ² ) = ( ^{3/2 1/2} ) · F · S ^{- 3 / 2 ·} R ^{- 1 / 2} . In the formula, F: The load value of the conductive particles when the 20% compressive deformation occurs (N) S: The compressive displacement of the conductive particles when the 20% compressive deformation occurs (mm) R: The radius of the conductive particles (mm).

By setting the 20% compressive elastic modulus of the high-hardness conductive particles to 8000 N/mm ² or more, even if an oxide film is formed on the terminal surface of the electronic parts, the oxide film can be pierced by the high-hardness conductive particles. In addition, By setting it to 28000 N/mm ² or less, the crimping force required for anisotropic conductive connection does not become too high, and a conventional pressing jig can be used for anisotropic conductive connection.

The particle size of the high-hardness conductive particles 1A is preferably 1 μm or more and 30 μm or less, more preferably 3 μm or more and less than 10 μm, in order to suppress an increase in on-resistance and suppress the occurrence of short circuits. The particle size of the conductive particles before being dispersed in the insulating resin layer can be measured by a general particle size distribution analyzer, and the average particle size can also be determined using a particle size distribution analyzer. It can be image type or laser type. As an image measuring apparatus, a wet floating particle size/shape analyzer FPIA-3000 (Malvern Corporation) can be mentioned as an example. The number of samples (the number of conductive particles) for measuring the average particle diameter D is preferably 1000 or more. The particle size of the conductive particles of the anisotropic conductive film can be determined by observation with an electron microscope such as SEM. In this case, the number of samples for measuring the average particle diameter is preferably 200 or more.

In addition, in the case of using those having insulating fine particles adhered to the surface thereof as conductive particles, the particle size of the conductive particles in the present invention refers to the particle size of the insulating fine particles not including the surface.

On the other hand, the 20% compressive elastic modulus of the low-hardness conductive particles 1B is lower than that of the high-hardness conductive particles, preferably 10% or more and 70% or less of the 20% compressive elastic modulus of the high-hardness conductive particles. If the 20% compressive elastic modulus of the low-hardness conductive particles 1B is too low, it becomes difficult to contribute to conduction. On the contrary, if it is too high, the difference in hardness with the high-hardness conductive particles becomes insufficient, and the effect of the present invention cannot be obtained. .

The particle size of the low-hardness conductive particles 1B is preferably 1 μm or more and 30 μm or less. As long as the particle size of the high-hardness conductive particles is 80% or more, there is no problem in practical application, and it is preferably equal to or more. By setting the particle size of the low-hardness conductive particles to be equal to or greater than the particle size of the high-hardness conductive particles, the low-hardness conductive particles will be easily formed by the cracks of the oxide film formed on the terminal surface by the high-hardness conductive particles. aid in conduction.

The high-hardness conductive particles 1A and the low-hardness conductive particles 1B having the above-mentioned hardness and particle diameter can be appropriately selected from the conductive particles used for known anisotropic conductive films. For example, metal particles such as nickel, cobalt, silver, copper, gold, and palladium, alloy particles such as solder, metal-coated resin particles, and metal-coated resin particles having insulating fine particles adhered to the surface thereof may be mentioned. The thickness of the metal layer of the metal-coated resin particles is preferably 50 nm to 250 nm. In addition, the conductive particles may also be provided with protrusions on the surface. In the case of metal-coated resin particles, those listed in Japanese Patent Laid-Open No. 2016-89153 can also be used.

<Number Density of Conductive Particles> The number density of the low-hardness conductive particles 1B is set to 10% or more of the entire conductive particles, and can be appropriately adjusted according to the type of the terminal to be connected or the connection conditions. As an example, it is preferably 20% or more and 80% or less, and more preferably 30% or more and 70% or less. Regardless of whether the number density of the low-hardness conductive particles relative to the entire conductive particles is too low or too high, it is difficult to obtain the effect of the present invention by mixing the high-hardness conductive particles and the low-hardness conductive particles.

In addition, the number density of the entire conductive particles is not particularly limited. As an example, when the average particle diameter D of the entire conductive particles 1A and 1B is less than 10 μm, it is preferably 6,000 particles/mm ² or more and 42,000 particles/ mm ² or less. When the average particle diameter is 10 μm or more, it is not limited to this range. As an example, it is 20 pieces/mm ² or more and 2000 pieces/mm ² or less.

When the average particle diameter D of the entire conductive particles 1A and 1B is less than 10 μm, if the number density of the entire conductive particles becomes too high, the area occupancy rate of the conductive particles calculated from the following formula also becomes too high. high. Area occupancy = [number density of conductive particles in plan view (items/mm ² )] × [average of the plan view areas of 1 conductive particle (mm ² /item)] × 100

The area occupancy rate is an index of the thrust required for the pressing jig for thermocompression bonding of the anisotropic conductive film to electronic components. By making the area occupancy ratio preferably 35% or less, and more preferably in the range of 0.3 to 30%, the pressing jig required for thermocompression bonding of the anisotropic conductive film to electronic components can be reduced. The thrust suppression is low.

In addition, the number density of conductive particles can be measured using an observation image obtained by a metal microscope or the like. In addition, it can also be calculated|required by measuring the observed image by image analysis software (for example, WinROOF, Mitani Corporation, etc.). In the case of obtaining the number density of the conductive particles, the measurement area is preferably a rectangular area with one side of 100 μm or more arbitrarily set at a plurality of locations (preferably 5 locations or more, more preferably 10 locations or more), The total area of the measurement regions is set to be 2 mm ² or more. The size or quantity of each area can be appropriately adjusted according to the state of the number density. In addition, the average value of the plan view area of one conductive particle can be calculated|required by measuring the observation image of the film surface obtained by the electron microscope, such as a metal microscope and SEM. Image analysis software can also be used. The observation method or the measurement method is not limited to the above-mentioned methods.

Further, the inter-particle distance Lg as the entire conductive particles 1A and 1B is appropriately set according to a specific number density and particle arrangement after the area occupancy rate of the conductive particles 1A and 1B is achieved.

<Arrangement of Conductive Particles> In the anisotropic conductive film of the present invention, the arrangement of the entire film of the conductive particles including the high-hardness conductive particles 1A and the low-hardness conductive particles 1B may be a regular arrangement or a random arrangement in plan view. As an aspect of the regular arrangement, in addition to the square lattice shown in FIG. 1A , a lattice arrangement such as a hexagonal lattice, a rhombic lattice, and a rectangular lattice can also be used. Moreover, as the particle arrangement|positioning of the whole electrically-conductive particle, the particle row|line|column which the electrically-conductive particle 1A or 1B is linearly arranged at predetermined intervals may be juxtaposed at predetermined intervals. The regular arrangement in the present invention is not particularly limited as long as it repeats in the longitudinal direction of the film.

On the other hand, each of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B may be regularly arranged. For example, as in the anisotropic conductive film 10B shown in FIGS. 2A and 2B , the number density of the low-hardness conductive particles 1B can be set to 50% of the entire conductive particles, and the high-hardness conductive particles 1A and the low-hardness conductive particles 1B can be are arranged in a square grid. In FIG. 2A , the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are alternately arranged, but the present invention includes both such strict arrangements and not such arrangements.

When the particle arrangement as a whole of the conductive particles has a lattice axis or an arrangement axis, the lattice axis or arrangement axis may be parallel to the longitudinal direction of the anisotropic conductive film 10A, or may be parallel to the longitudinal direction of the anisotropic conductive film. The cross direction can be determined according to the terminal width and terminal spacing to be connected. For example, in the case of producing an anisotropic conductive film for fine pitch, it is preferable to make at least one lattice axis A of the conductive particles 1A and 1B inclined with respect to the longitudinal direction of the anisotropic conductive film 10A as shown in FIG. 1A . The angle θ formed by the longitudinal direction of the terminal 20 connected by the anisotropic conductive film 10A and the lattice axis A is set to 16° to 74°.

In addition, it is preferable that the conductive particles 1A and 1B exist without contacting each other in a plan view of the film, and the conductive particles 1A and 1B also exist without overlapping each other in the film thickness direction. Therefore, the number ratio of the conductive particles 1A and 1B that exist without contacting each other is 95% or more, preferably 98% or more, and more preferably 99.5% or more with respect to the entire conductive particles. This situation is the same for both rule configuration and random configuration. When the conductive particles 1A and 1B are regularly arranged using a transfer mold as described below, the ratio at which the conductive particles 1A and 1B exist without contacting each other can be easily controlled, which is preferable. In the case of random arrangement, it is easy to knead the conductive particles 1A and 1B in the insulating resin to produce an anisotropic conductive film. Therefore, it is also possible to select the manufacturing method and utilization of the transfer mold based on the balance with performance or cost. Any of the manufacturing methods of kneading.

When the conductive particles 1A and 1B exist without contacting each other, the positions in the film thickness direction are preferably aligned. For example, when the particle diameters of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are equal, as shown in FIG. 1B , the embedded amounts Lb of the conductive particles 1A and 1B in the film thickness direction can be the same. That is, since the distance to one interface of the insulating resin layer 2 can be made uniform, the trapping property of the conductive particles of the terminal can be easily stabilized.

In addition, when the particle diameters of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are different, if the conductive particles 1A and 1B are embedded in the insulating resin layer 2, the surface of the insulating resin layer 2 is If the distances between the conductive particles 1A and 1B are the same, the trapping properties of the conductive particles of the terminal are easily stabilized for the same reason as described above. On the other hand, when the conductive particles 1A and 1B are exposed from the insulating resin layer 2 as shown in FIG. 3 , the conductive particles of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B may also be exposed from the insulating resin. The position of the exposed top of layer 2 in the film thickness direction is aligned. In addition, the relationship between the layer thickness La of the insulating resin layer 2 and the ratio (La/D) of the average particle diameter D of the conductive particles 1A and 1B will be described below.

When the particle sizes of the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are equal or different, if the conductive particles 1A and 1B are exposed from the insulating resin layer 2, the pressure applied during connection is easily transmitted to the Conductive particles 1A, 1B. Taking the case of metal-coated resin particles as an example to describe in detail, when the conductive particles 1A and 1B are exposed from the insulating resin layer 2, similarly to the functions of the recesses 2b and 2c described below, when anisotropic conductive connection occurs The resistance of the insulating resin layer 2 to the deformation of the metal-coated resin particles produced by pressing the metal-coated resin particles by a pressing jig is reduced, so that the state of the indentation after connection is easily made uniform. Thereby, it becomes easy to check the state after connection.

Here, the embedded amount Lb refers to the distance such that the conductive particles 1A, 1B are exposed on the surface of the insulating resin layer 2 in which the conductive particles 1A and 1B are embedded (the front and back surfaces of the insulating resin layer 2 are exposed). The surface on the side of 1B, or when the conductive particles 1A and 1B are completely embedded in the insulating resin layer 2, the surface that is closer to the conductive particles 1A and 1B) and the central portion of the adjacent conductive particles. The distance between the plane 2p and the deepest part of the conductive particles 1A and 1B. When the ratio of the embedded amount Lb of the conductive particles 1A and 1B to the average particle diameter D is set as the embedded ratio (Lb/D), the embedded ratio is preferably 30% or more and 105% or less.

When the embedding ratio (Lb/D) is 30% or more and less than 60%, the ratio of the particles exposed from the relatively high-viscosity resin that maintains the conductive particles increases, so that low-pressure packaging becomes easier. By setting it as 60% or more, it becomes easy to maintain electroconductive particle 1A, 1B in a specific particle dispersion state or specific arrangement|positioning by the insulating resin layer 2. Moreover, by setting it as 105% or less, the resin amount of the insulating resin layer which functions so that the conductive particle between terminals may flow unnecessarily at the time of anisotropic conductive connection can be reduced. In addition, the conductive particles 1A and 1B may penetrate through the insulating resin layer 2 , and the embedding ratio (Lb/D) in this case is 100%.

In addition, in the present invention, the numerical value of the buried ratio (Lb/D) refers to 80% or more of the total number of conductive particles contained in the anisotropic conductive film, preferably 90% or more, more preferably 96% or more It becomes the numerical value of the buried ratio (Lb/D). Therefore, the burying rate of 30% or more and 105% or less refers to 80% or more of the total number of conductive particles contained in the anisotropic conductive film, preferably 90% or more, more preferably 96% or more. 30% or more and 105% or less. By making the embedding ratio (Lb/D) of all the conductive particles uniform in this way, the load of pressing is applied to the conductive particles uniformly, so that the trapping state of the conductive particles in the terminal becomes good, and conduction reliability can be expected. In order to further improve the accuracy, 200 or more conductive particles may be measured and obtained.

In addition, in the measurement of the burial rate (Lb/D), a certain number of objects can be obtained at one time by adjusting the focus in the surface view image. Alternatively, a laser-type discriminating displacement sensor (manufactured by KEYENCE Co., Ltd., etc.) can also be used for the measurement of the embedded rate (Lb/D).

<Insulating resin layer> (Viscosity of insulating resin layer) In the anisotropic conductive film of the present invention, the minimum melt viscosity of the insulating resin layer 2 is not particularly limited, and can be appropriately determined according to the object of use of the anisotropic conductive film, the manufacturing method of the anisotropic conductive film, and the like. For example, as long as the following depressions 2b ( FIG. 4 ) and 2c ( FIG. 5 ) can be formed, the amount can be about 1000 Pa·s depending on the method of manufacturing the anisotropic conductive film. On the other hand, as a method for producing an anisotropic conductive film, a method of holding the conductive particles on the surface of the insulating resin layer in a specific arrangement and pressing the conductive particles into the insulating resin layer is performed. Since the insulating resin layer can be formed into a film, it is preferable to set the minimum melt viscosity of the insulating resin layer to 1100 Pa·s or more.

In addition, as described in the method of manufacturing an anisotropic conductive film described below, as shown in FIG. As shown, the depressions 2c are formed just above the conductive particles 1A, 1B pressed into the insulating resin layer 2, and in this respect, preferably 1500 Pa·s or more, more preferably 2000 Pa·s or more, and further It is preferably 3000 to 15000 Pa·s, more preferably 3000 to 10000 Pa·s. As an example, the minimum melt viscosity can be obtained by using a rotational rheometer (manufactured by TA instruments), keeping it fixed under a measuring pressure of 5 g, and using a measuring plate with a diameter of 8 mm. In the temperature range of 30 to 200° C., the temperature increase rate was set to 10° C./min, the measurement frequency was set to 10 Hz, and the load was changed by 5 g with respect to the above-mentioned measurement plate.

By setting the minimum melt viscosity of the insulating resin layer 2 to a high viscosity of 1500 Pa·s or more, the useless movement of the conductive particles during the crimping of the anisotropic conductive film to the article can be suppressed, especially the anisotropic conductive film can be prevented. Conductive particles that should be clamped between terminals during connection flow due to resin flow.

In addition, when the conductive particle dispersion layer 3 of the anisotropic conductive film 10A is formed by pressing the conductive particles 1A, 1B into the insulating resin layer 2, the insulating resin when the conductive particles 1A, 1B are pressed In the layer 2, when the conductive particles 1A and 1B are pressed into the insulating resin layer 2 so that the conductive particles 1A and 1B are exposed from the insulating resin layer 2, the insulating resin layer 2 is plastically deformed and the conductive particles 1A are formed. The insulating resin layer 2 around 1B forms a high-viscosity viscous body like the depression 2b (FIG. 4), or the conductive particles 1A and 1B are buried in the insulating resin layer 2 without being exposed from the insulating resin layer 2. When the conductive particles 1A and 1B are pressed into the conductive particles 1A and 1B in this manner, it becomes a viscous body with a high viscosity such as depressions 2c ( FIG. 5 ) are formed on the surface of the insulating resin layer 2 directly above the conductive particles 1A and 1B. Therefore, the lower limit of the viscosity of the insulating resin layer 2 at 60°C is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, further preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s s or less, more preferably 15000 Pa·s or less, still more preferably 10000 Pa·s or less. This measurement can be obtained by the same measurement method as the minimum melt viscosity, and the extraction temperature is a value of 60°C.

Regarding the specific viscosity of the insulating resin layer 2 when the conductive particles 1A and 1B are pressed into the insulating resin layer 2, the lower limit is preferably 3000 Pa·s or more depending on the shape and depth of the depressions 2b and 2c to be formed. , more preferably 4000 Pa·s or more, still more preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, and still more preferably 10000 Pa·s or less. Moreover, it is preferable to obtain such a viscosity at 40-80 degreeC, More preferably, it is 50-60 degreeC.

As described above, by forming the depressions 2b ( FIG. 4 ) around the conductive particles 1A and 1B exposed from the insulating resin layer 2 , the conductive particles 1A and 1B generated when the anisotropic conductive film is pressed against the article are formed. The resistance received from the insulating resin by the flattening of 1B is lower than that in the case where there is no recess 2b. Therefore, it becomes easy for the conductive particles to be pinched by the terminals at the time of anisotropic conductive connection, whereby the conduction performance is improved, and the trapping property is also improved.

In addition, by forming depressions 2c ( FIG. 5 ) on the surface of the insulating resin layer 2 just above the conductive particles 1A and 1B that are not exposed from the insulating resin layer 2 but buried The pressure at the time of crimping the oriented conductive film to the article tends to concentrate on the conductive particles 1A and 1B. Therefore, it becomes easy for the conductive particles to be pinched by the terminals at the time of anisotropic conductive connection, whereby the catchability is improved, and the conduction performance is improved.

＜"Incline" or "undulation" in place of depression＞ The "recesses" 2b and 2c of the anisotropic conductive film shown in Figs. 4 and 5 can also be described from the viewpoint of "slope" or "undulation". Hereinafter, description will be made with reference to the drawings ( FIGS. 8 to 15 ).

The anisotropic conductive film 100A is composed of the conductive particle-dispersed layer 3 ( FIG. 8 ). In the conductive particle dispersion layer 3 , the high-hardness conductive particles 1A and the low-hardness conductive particles 1B are regularly dispersed in a state of being exposed on one side of the insulating resin layer 2 . In the top view of the film, the conductive particles 1A and 1B are not in contact with each other, and in the film thickness direction, the conductive particles 1A and 1B also do not overlap each other and are regularly dispersed, forming a single unit where the positions of the conductive particles 1A and 1B in the film thickness direction are aligned. layer of conductive particles.

The surface 2a of the insulating resin layer 2 around each conductive particle 1A, 1B is formed with an inclination 2b with respect to the tangent plane 2p of the insulating resin layer 2 in the central portion between adjacent conductive particles. In addition, as described below, in the anisotropic conductive film of the present invention, undulations 2c may be formed on the surface of the insulating resin layer immediately above the conductive particles 1A and 1B embedded in the insulating resin layer 2 ( FIG. 11 ). , Figure 13).

In the present invention, "inclined" refers to a state in which the flatness of the surface of the insulating resin layer in the vicinity of the conductive particles 1A and 1B is impaired, a part of the resin layer is chipped relative to the tangential plane 2p, and the amount of resin decreases. In other words, with respect to the inclination, the surface of the insulating resin layer around the conductive particles is chipped with respect to the tangential plane. On the other hand, "undulation" refers to a state in which the resin is reduced due to the presence of undulations on the surface of the insulating resin layer directly above the conductive particles, and there are portions having a level difference like the undulations. In other words, the resin amount of the insulating resin layer directly above the conductive particles is smaller than when the surface of the insulating resin layer directly above the conductive particles is located on the tangent plane. These can be identified by comparing the portion corresponding to the directly above the conductive particles with the flat surface portion between the conductive particles ( FIG. 11 , 2 f of FIG. 13 ). In addition, there are also cases where the starting point of the undulation exists as a slope.

As described above, by forming the inclinations 2b ( FIG. 8 ) around the conductive particles 1A and 1B exposed from the insulating resin layer 2 , compared to the time when the conductive particles 1A and 1B are sandwiched between the terminals during anisotropic conductive connection The flattening of the generated conductive particles 1A and 1B reduces the resistance received from the insulating resin layer compared to the case where there is no inclination 2b, so that the conductive particles can be easily sandwiched between the terminals, thereby improving the conduction performance. improve. The inclination is preferably along the outer shape of the conductive particles. The reason for this is that, in addition to the effect of being connected more easily, it becomes easy to recognize the conductive particles, thereby facilitating inspection and the like at the time of producing an anisotropic conductive film. In addition, the inclination and the waviness may partially disappear due to "the insulating resin layer is subjected to hot pressing or the like", and the present invention includes such a case. In this case, the conductive particles may be exposed at one point on the surface of the insulating resin layer. In addition, regarding the anisotropic conductive film, since the electronic components to be connected are various and adjusted according to these, it is desirable to have a high degree of freedom in design so as to satisfy various requirements, so that the slope and the undulations are reduced or localized. The ground disappears and can be used.

In addition, by forming the undulations 2c on the surface of the insulating resin layer 2 directly above the conductive particles 1A and 1B that are not exposed from the insulating resin layer 2 but buried , the pressing force from the terminal is easily applied to the conductive particles during anisotropic conductive connection. In addition, due to the undulations, the amount of resin directly above the conductive particles is reduced compared to the case where the resin is flatly stacked, so that the resin directly above the conductive particles during connection is easily removed, and the terminals and the conductive particles are easily contacted. The captureability of the conductive particles is improved, and the conduction reliability is improved.

(Position of conductive particles in the thickness direction of the insulating resin layer) The positions of the conductive particles 1A and 1B in the thickness direction of the insulating resin layer 2 when considering the situation of "tilting" or "undulation" are the same as the above, and the conductive particles 1A and 1B can be removed from the insulating resin layer 2 Exposed or buried in the insulating resin layer 2 without being exposed, the distance from the tangent plane 2p of the central part between the adjacent conductive particles to the deepest part of the conductive particles (hereinafter referred to as the buried amount) Lb and the conductive particles The ratio of the average particle diameter D of the particles (Lb/D) (hereinafter referred to as the entrapment ratio) is preferably 30% or more and 105% or less.

By setting the burying ratio (Lb/D) to 30% or more, the conductive particles 1A and 1B can be maintained in a specific particle dispersion state or a specific arrangement by the insulating resin layer 2 , and by setting it to 105% Hereinafter, it is possible to reduce the resin amount of the insulating resin layer which functions so that the conductive particles between the terminals flow unnecessarily at the time of anisotropic conductive connection.

In addition, the numerical value of the burying ratio (Lb/D) refers to 80% or more, preferably 90% or more, more preferably 96% or more of the total number of conductive particles contained in the anisotropic conductive film. (Lb/D) value. Therefore, the term "implantation rate of 30% or more and 105% or less" refers to the embedding rate of 80% or more, preferably 90% or more, and more preferably 96% or more of the total number of conductive particles contained in the anisotropic conductive film. 30% or more and 105% or less. By making the embedding ratio (Lb/D) of all the conductive particles uniform in this way, the load of pressing is applied to the conductive particles uniformly, so that the trapping state of the conductive particles in the terminal becomes good, and the conduction reliability is improved.

The burial ratio (Lb/D) can be obtained by the following method: 10 or more regions with an area of 30 ^mm2 or more are arbitrarily extracted from the anisotropic conductive film, and a part of the cross section of the film is observed using an SEM image , and a total of 50 or more conductive particles were measured. In order to further improve the accuracy, it can also be obtained by measuring 200 or more conductive particles.

In addition, in the measurement of the burial rate (Lb/D), a certain number of objects can be obtained at one time by adjusting the focus in the surface view image. Alternatively, a laser-type discriminating displacement sensor (manufactured by KEYENCE Co., Ltd., etc.) can be used for the measurement of the embedded rate (Lb/D).

(Embedding rate of more than 30% and less than 60%) As a more specific embodiment of embedding the conductive particles 1A and 1B having an embedding ratio (Lb/D) of 30% or more and less than 60%, first, the anisotropic conductive film 100A shown in FIG. 8 can be mentioned. The conductive particles 1A and 1B are embedded so as to be exposed from the insulating resin layer 2 with a burying rate of 30% or more and less than 60%. The anisotropic conductive film 100A has an inclination 2b, and the inclination 2b is the part of the surface of the insulating resin layer 2 in contact with the conductive particles 1A and 1B exposed from the insulating resin layer 2 and the vicinity thereof with respect to the adjacent conductive particles The tangent plane 2p of the surface 2a of the insulating resin layer in the central part between the particles is substantially along the ridgeline of the outer shape of the conductive particles.

In the case of manufacturing the anisotropic conductive film 100A by pressing the conductive particles 1A, 1B into the insulating resin layer 2, such inclination 2b or the following undulations 2c can be obtained by pressing the conductive particles 1A and 1B at 3000°C at 40-80°C. The viscosity of ∼20000 Pa·s, more preferably 4500 to 15000 Pa·s, is formed by pressing the conductive particles 1A and 1B.

(Embedding rate of more than 60% and less than 100%) As a more specific embedding form of the conductive particles 1A and 1B having a burying ratio (Lb/D) of 60% or more and less than 100%, first, conductive particles such as the anisotropic conductive film 100A shown in FIG. 8 can be mentioned. 1A and 1B are embedded at a burying rate of 60% or more and less than 100% so as to be exposed from the insulating resin layer 2 . The anisotropic conductive film 100A has an inclination 2b, and the inclination 2b is the part of the surface of the insulating resin layer 2 in contact with the conductive particles 1A and 1B exposed from the insulating resin layer 2 and the vicinity thereof with respect to the adjacent conductive particles The tangent plane 2p of the surface 2a of the insulating resin layer in the central part between the particles is substantially along the ridgeline of the outer shape of the conductive particles.

With regard to such inclination 2b or the following undulations 2c, in the case of manufacturing the anisotropic conductive film 100A by press-fitting the conductive particles 1A, 1B into the insulating resin layer 2, when the conductive particles 1A, 1B are press-fitted The lower limit of the viscosity is preferably 3000 Pa·s or more, more preferably 4000 Pa·s or more, further preferably 4500 Pa·s or more, and the upper limit is preferably 20000 Pa·s or less, more preferably 15000 Pa·s or less, More preferably, it is 10000 Pa·s or less. Moreover, it is preferable to obtain such a viscosity at 40-80 degreeC, More preferably, it is 50-60 degreeC. In addition, the inclination 2b or part of the undulations 2c may disappear due to hot pressing of the insulating resin layer, or the inclination 2b may be changed into the undulations 2c, and the conductive particles having the undulations 2c may be 1 of the tops thereof. The dots are exposed to the insulating resin layer 2 .

(The state of 100% burial rate) Next, as an aspect of the burying ratio (Lb/D) of 100% in the anisotropic conductive film of the present invention, as in the anisotropic conductive film 100B shown in FIG. The periphery has a "slope 2b that is substantially along the ridgeline of the outer shape of the conductive particles substantially the same as that of the anisotropic conductive film 100A shown in FIG. 8", and the exposed diameter Lc of the conductive particles 1A and 1B exposed from the insulating resin layer 2 is smaller than The average particle size D of the conductive particles; like the anisotropic conductive film 100C shown in FIG. 10A , the inclination 2b around the exposed portions of the conductive particles 1A, 1B appears steeply in the vicinity of the conductive particles 1A, 1B, and the conductive particles The exposed diameter Lc of 1A and 1B is approximately equal to the average particle diameter D of the conductive particles; like the anisotropic conductive film 100D shown in FIG. 1A and 1B are exposed from the insulating resin layer 2 at one point of the top 1a.

In addition, a minute protruding portion 2q may be formed adjacent to the inclination 2b of the insulating resin layer 2 around the exposed portion of the conductive particle, or the undulation 2c of the insulating resin layer just above the conductive particle. This example is shown in FIG. 10B .

Since the anisotropic conductive films 100B ( FIG. 9 ), 100C ( FIG. 10A ), and 100D ( FIG. 11 ) have a burying ratio of 100%, the tops 1 a of the conductive particles 1A and 1B and the surface 2 a of the insulating resin layer 2 Align to the same side. When the tops 1a of the conductive particles 1A and 1B and the surface 2a of the insulating resin layer 2 are aligned on the same plane, there is an effect similar to the case where the conductive particles 1A and 1B protrude from the insulating resin layer 2 as shown in FIG. 8 . In contrast, in the case of anisotropic conductive connection, the amount of resin in the film thickness direction is less likely to become uneven around each conductive particle, which can reduce the movement of conductive particles caused by resin flow. In addition, even if the embedding rate is not strictly 100%, if the tops 1a of the conductive particles 1A and 1B embedded in the insulating resin layer 2 and the surface 2a of the insulating resin layer 2 are aligned to the extent that they become the same plane obtain this effect. In other words, when the embedding ratio (Lb/D) is approximately 80 to 105%, particularly 90 to 100%, it can be considered that the conductive particles 1A and 1B embedded in the insulating resin layer 2 are embedded in the tops 1a and the insulating resin. The surface 2a of the layer 2 is the same surface, which can reduce the movement of the conductive particles caused by the resin flow.

In these anisotropic conductive films 100B ( FIG. 9 ), 100C ( FIG. 10A ), and 100D ( FIG. 11 ), since the amount of resin around the conductive particles 1A and 1B is less likely to become uneven in 100D, the amount of resin around the conductive particles 1A and 1B can be eliminated. The movement of the conductive particles due to the flow is also one point of the top part 1a, but the conductive particles 1A and 1B are exposed from the insulating resin layer 2, so the following effects can be expected: the trapping properties of the conductive particles 1A and 1B of the terminals are also expected. Good, and it is not easy to generate slight movement of conductive particles. Therefore, this aspect is particularly effective in the case of fine pitches or narrow inter-bump spaces.

In addition, the anisotropic conductive films 100B ( FIG. 9 ), 100C ( FIG. 10A ), and 100D ( FIG. 11 ) having different shapes and depths of the inclination 2 b and the undulation 2 c can be pressed into the conductive particles 1A and 1B by changing as follows The viscosity of the insulating resin layer 2 and the like are produced.

(The state where the burial rate exceeds 100%) In the anisotropic conductive film of the present invention, when the burying rate exceeds 100%, the conductive particles 1A and 1B like the anisotropic conductive film 100E shown in FIG. 12 are exposed and have the exposed portion. The inclination 2b of the surrounding insulating resin layer 2 with respect to the tangent plane 2p or the undulation 2c with respect to the tangent plane 2p of the insulating resin layer 2 immediately above the conductive particles 1A and 1B ( FIG. 13 ).

In addition, the insulating resin layer 2 around the exposed portions of the conductive particles 1A, 1B has an anisotropic conductive film 100E ( FIG. 12 ) with a slope 2b, and the insulating resin layer 2 directly above the conductive particles 1A, 1B has The anisotropic conductive film 100F ( FIG. 13 ) of the undulations 2c can be produced by changing the viscosity of the insulating resin layer 2 when the conductive particles 1A and 1B are pressed into the isotropic film, and the like.

In addition, when the anisotropic conductive film 100E shown in FIG. 12 is used for anisotropic conductive connection, since the conductive particles 1A and 1B are directly pressed by the terminals, the captureability of the conductive particles at the terminals is improved. In addition, when the anisotropic conductive film 100F shown in FIG. 13 is used for anisotropic conductive connection, the conductive particles 1A and 1B do not directly press the terminals, but press through the insulating resin layer 2, but the pressing direction The amount of resin present is the same as that in the state of FIG. 15 (that is, the conductive particles 1A and 1B are embedded with an embedding rate exceeding 100%, the conductive particles 1A and 1B are not exposed from the insulating resin layer 2 , and the insulating resin layer 2 Compared with the flat surface state), the pressing force is easily applied to the conductive particles, and the conductive particles 1A and 1B between the terminals can be prevented from moving unnecessarily due to the resin flow during anisotropic conductive connection.

It is easy to obtain the inclination 2b of the insulating resin layer 2 around the exposed portion of the conductive particles (FIG. 8, FIG. 9, FIG. 10A, FIG. 12), or the undulation 2c of the insulating resin layer just above the conductive particles (FIG. 11. In terms of the effect of Fig. 13), the ratio (Le/D) of the maximum depth Le of the inclination 2b to the average particle diameter D of the conductive particles 1A and 1B is preferably less than 50%, more preferably less than 30%. %, more preferably 20-25%, and the ratio (Ld/D) of the maximum diameter Ld of the inclination 2b or the undulation 2c to the average particle diameter D of the conductive particles 1A and 1B is preferably 100% or more, more preferably 100- 150%, the ratio (Lf/D) of the maximum depth Lf of the undulations 2c to the average particle size D of the conductive particles 1A and 1B is greater than 0, preferably less than 10%, more preferably 5% or less.

In addition, the diameter Lc of the exposed (right above) portion of the conductive particles 1A and 1B of the inclined 2b or undulation 2c can be set to be equal to or less than the average particle diameter D of the conductive particles 1A and 1B, preferably 10 to 90% of the average particle diameter D . One point of the top of the conductive particles 1A and 1B may be exposed, or the conductive particles 1A and 1B may be completely buried in the insulating resin layer 2 so that the diameter Lc becomes zero.

In addition, as shown in FIG. 14 , in the anisotropic conductive film 100G having a burying ratio (Lb/D) of less than 60%, the conductive particles 1A and 1B are easily rotated on the insulating resin layer 2 , so that the anisotropy is improved. In terms of the capture rate at the time of the electrically conductive connection, it is preferable to set the burying rate (Lb/D) to 60% or more.

In addition, in the aspect (Lb/D) in which the burying ratio exceeds 100%, when the surface of the insulating resin layer 2 is flat like the anisotropic conductive film 100X of the comparative example shown in FIG. 15 , interposed The amount of resin between the conductive particles 1A, 1B and the terminal becomes excessive. In addition, since the conductive particles 1A and 1B press the terminal without directly contacting the terminal, but press the terminal through the insulating resin layer, the conductive particles are also likely to flow due to the resin flow.

In the present invention, the existence of the inclination 2b and the undulation 2c on the surface of the insulating resin layer 2 can be confirmed by observing the cross section of the anisotropic conductive film with a scanning electron microscope, and it can also be observed in the surface field of view. Undergo verification. The inclination 2b and the undulation 2c can also be observed using an optical microscope or a metal microscope. In addition, the magnitude of the inclination 2b and the waviness 2c can also be confirmed by adjusting the focus during image observation or the like. The same is true even after the inclination or undulation is reduced by hot pressing as described above. The reason for this is that sometimes traces remain.

(Composition of insulating resin layer) The insulating resin layer 2 is preferably formed of a curable resin composition, for example, a thermopolymerizable composition containing a thermopolymerizable compound and a thermopolymerization initiator. The thermally polymerizable composition may contain a photopolymerization initiator if necessary.

When a thermal polymerization initiator and a photopolymerization initiator are used in combination, those that function as both a thermally polymerizable compound and a photopolymerizable compound may be used, and in addition to the thermally polymerizable compound, a photopolymerizable compound may be used. polymeric compound. It is preferable to contain a photopolymerizable compound in addition to the thermally polymerizable compound. For example, a thermal cationic polymerization initiator is used as the thermal polymerization initiator, an epoxy compound is used as the thermal polymerizable compound, a photoradical polymerization initiator is used as the photopolymerization initiator, and an acrylate compound is used as the photopolymerizable compound .

As a photopolymerization initiator, a plurality of types that react with light having different wavelengths may be contained. Thereby, the wavelength used for photohardening of the resin constituting the insulating resin layer in the production of the anisotropic conductive film and the photohardening of the resin for bonding electronic components to each other during the anisotropic conductive connection can be used separately.

In the photocuring at the time of manufacturing an anisotropic conductive film, all or a part of the photopolymerizable compound contained in the insulating resin layer can be photocured. By this photocuring, the arrangement of the conductive particles 1A and 1B in the insulating resin layer 2 can be maintained or immobilized, and the suppression of short circuits and the improvement of trapping are expected. Moreover, the viscosity of the insulating resin layer in the manufacturing process of anisotropic conductive film can also be adjusted suitably by this photohardening. In particular, the photocuring is preferably performed when the ratio (La/D) of the layer thickness La of the insulating resin layer 2 to the average particle diameter D of the conductive particles 1A and 1B is less than 0.6. The reason for this is that, when the thickness of the insulating resin layer 2 is relatively thin with respect to the diameter of the conductive particles, the arrangement of the conductive particles is more reliably maintained or fixed in the insulating resin layer 2, and the insulating properties are improved. Adjustment of the viscosity of the resin layer 2 suppresses a decrease in yield in the connection of electronic components using the anisotropic conductive film.

The blending amount of the photopolymerizable compound in the insulating resin layer is preferably 30% by mass or less, more preferably 10% by mass or less, and more preferably less than 2% by mass. The reason for this is that when there are too many photopolymerizable compounds, the thrust applied by pressing at the time of connection increases.

Examples of the thermally polymerizable composition include a thermally radically polymerizable acrylate-based composition containing a (meth)acrylate compound and a thermal radical polymerization initiator, and an epoxy compound and a thermally cationic polymerization initiator. The thermal cationically polymerizable epoxy-based composition, etc. In place of the thermally cationically polymerizable epoxy-based composition containing a thermally cationic polymerization initiator, a thermally anionic polymerizable epoxy-based composition containing a thermally anionic polymerization initiator may also be used. Moreover, as long as there is no particular hindrance, a plurality of polymerizable compounds may be used in combination. As an example of combined use, the combined use of a cationically polymerizable compound and a radically polymerizable compound, etc. are mentioned.

Here, as the (meth)acrylate compound, a conventionally known thermally polymerizable (meth)acrylate monomer can be used. For example, a monofunctional (meth)acrylate-based monomer and a polyfunctional (meth)acrylate-based monomer having a difunctional or higher level can be used.

As a thermal radical polymerization initiator, an organic peroxide, an azo type compound, etc. are mentioned, for example. In particular, an organic peroxide that does not generate nitrogen gas which causes bubbles can be preferably used.

The usage-amount of the thermal radical polymerization initiator is preferably 2 to 60 parts by mass with respect to 100 parts by mass of the (meth)acrylate compound, since too little will lead to poor curing, and if too much, the life of the product will be shortened. , more preferably 5 to 40 parts by mass.

Examples of the epoxy compound include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, modified epoxy resins thereof, alicyclic epoxy resins, and the like. Two or more of these are used in combination. In addition to the oxetane compound, an epoxy compound may be used in combination.

As the thermal cationic polymerization initiator, known thermal cationic polymerization initiators for epoxy compounds can be used, for example, iodonium salts, periconium salts, phosphonium salts, ferrocenes, etc., which generate acids by heat, can be used, especially Aromatic permanium salts showing good latency to temperature can be preferably used.

Regarding the usage amount of the thermal cationic polymerization initiator, if it is too small, the curing tends to be poor, and if it is too large, the product life tends to be shortened. Therefore, it is preferably 2 to 60 parts by mass relative to 100 parts by mass of the epoxy compound. , more preferably 5 to 40 parts by mass.

The thermally polymerizable composition preferably contains a film-forming resin or a silane coupling agent. Examples of film-forming resins include phenoxy resins, epoxy resins, unsaturated polyester resins, saturated polyester resins, urethane resins, butadiene resins, polyimide resins, polyamide resins, and polyolefins. Resins and the like can be used in combination of two or more of these. Among these, a phenoxy resin can be preferably used from the viewpoint of film formability, workability, and connection reliability. The weight average molecular weight is preferably 10,000 or more. Moreover, as a silane coupling agent, an epoxy-type silane coupling agent, an acryl-type silane coupling agent, etc. are mentioned. These silane coupling agents are mainly alkoxysilane derivatives.

The thermopolymerizable composition may contain an insulating filler in addition to the above-mentioned conductive particles 1A and 1B in order to adjust the melt viscosity. Examples of the insulating filler include silica powder, alumina powder, and the like. The insulating filler is preferably a small filler with a particle size of 20 to 1000 nm, and the blending amount is preferably 5 to 50 parts by mass relative to 100 parts by mass of a thermopolymerizable compound (photopolymerizable compound) such as an epoxy compound. share.

The anisotropic conductive film of the present invention may contain fillers, softeners, accelerators, antiaging agents, colorants (pigments, dyes), organic solvents, ion scavengers, and the like in addition to the above-mentioned insulating fillers.

(layer thickness of insulating resin layer) In the anisotropic conductive film of the present invention, the lower limit of the ratio (La/D) of the layer thickness La of the insulating resin layer 2 to the average particle diameter D of the conductive particles 1A and 1B can be set for the following reasons: It is 0.3 or more, and the upper limit can be made 10 or less. Therefore, the ratio is preferably 0.3 to 10, more preferably 0.6 to 8, and still more preferably 0.6 to 6. Here, the average particle diameter D of the conductive particles 1A and 1B refers to the average particle diameter. If the layer thickness La of the insulating resin layer 2 is too large, the conductive particles 1A and 1B are likely to be displaced due to resin flow during anisotropic conductive connection, and the trapping properties of the conductive particles 1A and 1B of the terminals are reduced. When this ratio (La/D) exceeds 10, since this tendency becomes remarkable, it is more preferable that it is 8 or less, and it is still more preferable that it is 6 or less. Conversely, if the layer thickness La of the insulating resin layer 2 is too small and the ratio (La/D) is less than 0.3, it is difficult to maintain the conductive particles 1A and 1B in a specific particle dispersion state or a specific arrangement by the insulating resin layer 2 . Therefore, the ratio (La/D) is preferably 0.3 or more, and is more preferably 0.6 or more in terms of reliably maintaining a specific particle dispersion state or a specific arrangement by the insulating resin layer 2 . In addition, when the terminal to be connected is high-density COG, the ratio (La/D) of the layer thickness La of the insulating resin layer 2 to the average particle diameter D of the conductive particles 1A and 1B is preferably 0.8 to 2.

On the other hand, when the average particle diameter D is 10 μm or more, the upper limit of La/D is 3.5 or less, preferably 2.5 or less, more preferably 2 or less, and the lower limit is 0.8 or more, preferably is 1 or more, more preferably more than 1.3.

Regardless of the size of the average particle diameter D, if the layer thickness La of the insulating resin layer 2 is too large and the ratio becomes too large, the conductive particles 1A and 1B are difficult to press against the terminals during anisotropic conductive connection, and the conductive particles are easily Flow due to resin flow. Therefore, the positional displacement of the conductive particles is likely to occur, and the captureability of the conductive particles in the terminal is lowered. In addition, in order to press the conductive particles against the terminals, the thrust required for the pressing jig also increases, which hinders low-voltage assembly. Conversely, when the layer thickness La of the insulating resin layer 2 is too small and the ratio becomes too small, it becomes difficult to maintain the conductive particles 1A and 1B in a specific arrangement by the insulating resin layer 2 .

＜Transformation pattern＞ As the anisotropic conductive film of the present invention, a second insulating resin layer 4 having a lower minimum melt viscosity than the resin constituting the insulating resin layer 2 can be laminated on the conductive particle dispersion layer 3 ( FIGS. 6 and 7 ). The second insulating resin layer 4 can fill the space formed by terminals such as bumps of electronic components during anisotropic conductive connection, thereby improving the adhesion between the opposing electronic components. That is, in order to realize the low-voltage packaging of electronic components using the anisotropic conductive film, and to suppress the resin flow of the insulating resin layer 2 during anisotropic conductive connection, it is preferable to improve the particle trapping properties of the conductive particles 1A and 1B. In order to increase the viscosity of the insulating resin layer 2 and reduce the thickness of the insulating resin layer 2 within the range where the positional displacement of the conductive particles 1A and 1B does not occur, if the thickness of the insulating resin layer 2 becomes too thin, the Since there is a shortage of the amount of resin for adhering the opposing electronic components to each other, there is a possibility that the adhesiveness may be lowered. On the other hand, by providing the second insulating resin layer 4 with a lower viscosity than the insulating resin layer 2 during the anisotropic conductive connection, the adhesiveness of the electronic components can also be improved. Due to the flow of the second insulating resin layer 4 The property is higher than that of the insulating resin layer 2, so it is difficult to hinder the clamping or pressing of the conductive particles 1A and 1B using the terminals.

In the case of laminating the second insulating resin layer 4 on the conductive particle dispersion layer 3, it is preferable to stick the second insulating resin layer 4 on the surface of the depression 2b regardless of whether the second insulating resin layer 4 is located on the surface where the depressions 2b are formed. Electronic components that are pressurized with a tool (the insulating resin layer 2 is attached to the electronic components placed on the stage). Thereby, useless movement of the conductive particles can be avoided, and trapping properties can be improved.

The greater the difference in the minimum melt viscosity ratio between the insulating resin layer 2 and the second insulating resin layer 4, the easier it is for the spaces formed by the electrodes or bumps of electronic components to be filled with the second insulating resin layer 4, and the higher the electron density is. Adhesion of parts to each other. In addition, the greater the difference, the less the amount of movement of the insulating resin layer 2 in the conductive particle-dispersed layer 3 is relatively small, and the conductive particles 1A and 1B between the terminals are less likely to flow due to the resin flow. Since the capturing properties of the particles 1A and 1B are improved, they are preferable. In practical application, the minimum melt viscosity of the insulating resin layer 2 and the second insulating resin layer 4 is preferably 2 or more, more preferably 5 or more, and still more preferably 8 or more. On the other hand, if the ratio is too large, when the long anisotropic conductive film is made into a roll, there is a risk of resin overflow or sticking, so in practice, it is preferably 15 or less. More specifically, the preferred minimum melt viscosity of the second insulating resin layer 4 satisfies the above ratio, and is 3000 Pa·s or less, preferably 2000 Pa·s or less, especially 100 to 2000 Pa·s.

In addition, the second insulating resin layer 4 can be formed by adjusting the viscosity in the same resin composition as the insulating resin layer 2 .

In addition, the layer thickness of the second insulating resin layer 4 is preferably 4 to 20 μm. Alternatively, it is preferably 1 to 8 times as large as the average particle diameter D of the conductive particles 1A and 1B.

In addition, the minimum melt viscosity of the entire anisotropic conductive films 10F and 10G obtained by combining the insulating resin layer 2 and the second insulating resin layer 4 is practically 8000 Pa·s or less, preferably 200 to 7000 Pa·s, more preferably 200 to 4000 Pa·s.

As a specific lamination state of the second insulating resin layer 4, for example, when the conductive particles 1A and 1B protrude from one side of the insulating resin layer 2 like the anisotropic conductive film 10F shown in FIG. This protruding area is layered with the second insulating resin layer 4 so that the conductive particles 1A and 1B are immersed in the second insulating resin layer 4 . When the embedding ratio (Lb/D) of the conductive particles 1A and 1B is 0.95 or less, it is preferable to laminate the second insulating resin layer 4 in this way, and it is more preferable when it is 0.9 or less. In addition, when the average particle diameter D is less than 10 μm, it is preferable to laminate in this way.

On the other hand, as in the anisotropic conductive film 10G shown in FIG. 7 , the second insulating resin may be laminated on the “surface on the opposite side to the surface of the insulating resin layer 2 in which the conductive particles 1A and 1B are embedded”. Layer 4.

(3rd insulating resin layer) A third insulating resin layer may be provided on the opposite side to the second insulating resin layer 4 with the insulating resin layer 2 interposed therebetween. The third insulating resin layer can function as an adhesive layer. Similar to the second insulating resin layer 4 , it may be provided to fill spaces formed by electrodes or bumps of electronic components.

The resin composition, viscosity and thickness of the third insulating resin layer may be the same as or different from those of the second insulating resin layer 4 . The minimum melt viscosity of the anisotropic conductive film formed by combining the insulating resin layer 2, the second insulating resin layer 4 and the third insulating resin layer is not particularly limited. It is preferably 200 to 7000 Pa·s, more preferably 200 to 4000 Pa·s.

<Manufacturing method of anisotropic conductive film> The anisotropic conductive film of the present invention can be produced, for example, by holding the conductive particles 1A and 1B on the surface of the insulating resin layer 2 in an independent specific regular arrangement or a random dispersion state, and using a flat plate Alternatively, the conductive particles 1A and 1B may be pressed into the insulating resin layer 2 by a roller.

Here, the embedding amount Lb of the conductive particles 1A, 1B in the insulating resin layer 2 can be adjusted by the pressing force, temperature, etc. when the conductive particles 1A, 1B are pressed, and the presence or absence and shape of the recesses 2b, 2c and the depth can be adjusted by the viscosity of the insulating resin layer 2 during pressing, the pressing speed, the temperature, and the like.

In addition, the method for holding the conductive particles 1A and 1B in the insulating resin layer 2 is not particularly limited, but when the conductive particles 1A and 1B are arranged in a regular manner, for example, a transfer mold is used to make a specific ratio. The mixed conductive particles 1A and 1B are held in the insulating resin layer 2 . As a transfer mold, for example, a transfer mold material that is formed by known openings such as photolithography for inorganic materials such as silicon, various ceramics, glass, and metals such as stainless steel, or organic materials such as various resins can be used. method to form those with openings. In addition, the transfer mold may take a shape such as a plate shape, a roll shape, or the like.

As a method for obtaining the conductive particles 1A and 1B of the insulating resin layer 2 that are independent of each other in a random dispersed state, the insulating resin layer 2 can also be formed by kneading (mixing) the conductive particles 1A and 1B at a specific ratio. The resin composition was coated on the release film to obtain an insulating resin layer in which the conductive particles 1A and 1B were located at random positions.

In order to economically connect electronic components using the anisotropic conductive film, the anisotropic conductive film is preferably elongated to some extent. Therefore, the length of the anisotropic conductive film is preferably 5 m or more, more preferably 10 m or more, and still more preferably 25 m or more. On the other hand, if the anisotropic conductive film is made too long, a conventional connection device cannot be used. This conventional connection device is used by the user in the case of manufacturing electronic components using the anisotropic conductive film, and the operability is also reduced. poor. Therefore, the length of the anisotropic conductive film is preferably 5000 m or less, more preferably 1000 m or less, and still more preferably 500 m or less. From the viewpoint of excellent workability, it is preferable to use such a long body of an anisotropic conductive film as a roll body wound into a core.

<How to use anisotropic conductive film> The anisotropic conductive film of the present invention can be used to anisotropically conductively connect first electronic parts such as IC chips, IC modules, and FPCs to second electronic parts such as FPC, glass substrates, plastic substrates, rigid substrates, and ceramic substrates. It is preferably used, especially as a plastic substrate, for example, a PET base material that is easily deformed or cracked by crimping under high pressure has terminals formed thereon. In addition, the PET base material may be a polyimide base material laminated via an adhesive. As an example, the total thickness of these may be set to 0.15 mm or less. IC chips or wafers can also be stacked using the anisotropic conductive film of the present invention to be multi-layered. In addition, the electronic component connected by the anisotropic conductive film of this invention is not limited to the above-mentioned electronic component. In recent years, it can be used for a variety of electronic parts. The present invention also includes a connection structure in which electronic components are anisotropically conductively connected to each other using the anisotropic conductive film of the present invention. Moreover, the manufacturing method of the connection structure which has the process of disposing the anisotropic conductive film of this invention between a 1st electronic component and a 2nd electronic component, and performing anisotropic conductive connection is also included.

As a method of connecting electronic components using anisotropic conductive film, when the resin layer of the anisotropic conductive film is constituted by a single layer of conductive particle dispersion layer 3, it can be produced by the following method: Electronic components are temporarily attached and temporarily crimped from the side where the conductive particles 1A and 1B are embedded in the surface of the anisotropic conductive film, and the conductive particles 1A and 1B are not embedded in the surface of the temporarily crimped anisotropic conductive film. On the other side, the first electronic components such as IC chips are aligned and thermocompression bonded. When the insulating resin layer of the anisotropic conductive film contains not only a thermal polymerization initiator and a thermal polymerizable compound, but also a photopolymerization initiator and a photopolymerizable compound (which may be the same as the thermal polymerizable compound) When it is used, it can also be a crimping method that uses light and heat together. In this way, unexpected movement of the conductive particles can be suppressed to a minimum. In addition, the side where the conductive particles are not embedded may be temporarily attached to the second electronic component and used. Moreover, the anisotropic conductive film may be temporarily attached to a 1st electronic component instead of a 2nd electronic component.

In addition, when the anisotropic conductive film is formed of a laminate of the conductive particle-dispersed layer 3 and the second insulating resin layer 4, the conductive particle-dispersed layer 3 is temporarily attached to a second electronic component such as various substrates, and is temporarily pressed. Then, the 1st electronic components, such as an IC chip, are aligned with "the 2nd insulating resin layer 4 side of the anisotropic conductive film by temporary pressure bonding", and are mounted and thermocompression-bonded. The second insulating resin layer 4 side of the anisotropic conductive film may be temporarily attached to the first electronic component. In addition, the conductive particle-dispersed layer 3 side may be temporarily attached to the first electronic component and used. Example

Hereinafter, the present invention will be specifically described based on examples.

Examples 1 to 4, Comparative Examples 1 and 2 (1) Manufacture of anisotropic conductive film The resin composition for insulating resin layer formation which forms a conductive particle dispersion layer, and the resin composition for 2nd insulating resin layer formation were prepared by the composition shown in Table 1, respectively. The minimum melt viscosity of the insulating resin layer is 3000 Pa·s or more, and the ratio of the minimum melt viscosity of the insulating resin layer to the minimum melt viscosity of the second insulating resin layer is 2 or more.

On the other hand, prepared high-hardness conductive particles (20% compressive elastic modulus 22000) with about 70 alumina particles (average particle size 150 nm) on the surface of the resin core particles and a Ni layer (thickness 100 nm) on the outermost layer N/mm ² , average particle size 3 μm, manufactured by Sekisui Chemical Industry Co., Ltd.) (manufactured by the method described in Japanese Patent Laid-Open No. 2006-269296), and prepared with the same structure as high-hardness conductive particles Low-hardness conductive particles (20% compressive elastic modulus 6000 N/mm ² , average particle size 3 μm, manufactured by Sekisui Chemical Industry Co., Ltd.). Moreover, also in the following Examples 1-24 and Comparative Examples 1-10, the conductive particle by Sekisui Chemical Industry Co., Ltd. manufactured similarly was prepared.

The high-hardness conductive particles and the low-hardness conductive particles are mixed into the resin composition for forming the insulating resin layer (high-viscosity resin layer) so that the number density of the conductive particles is equal to that shown in Table 2, and is coated with a bar. It was coated on a PET film with a film thickness of 50 μm by a cloth machine, and dried in an oven at 80°C for 5 minutes to form a conductive particle dispersion with high-hardness conductive particles and low-hardness conductive particles randomly dispersed on the PET film. Floor. The thickness of the insulating resin layer of the conductive particle dispersion layer was 6 μm. In addition, the resin composition for forming a second insulating resin layer was coated on a PET film having a film thickness of 50 μm using a bar coater, and was dried in an oven at 80° C. for 5 minutes to form a coating on the PET film. A resin layer to be the second insulating resin layer with a thickness of 12 μm was formed. This resin layer was laminated|stacked on the said electroconductive particle dispersion layer, and an anisotropic electroconductive film was produced.

[Table 1] composition parts by mass Insulating resin layer (high viscosity resin) Phenoxy resin (Nippon Steel & Sumitomo Metal Chemical Co., Ltd. YP-50) 40 Silica filler (Japan Aerosil Co., Ltd., Aerosil R805) 25 Liquid epoxy resin (Mitsubishi Chemical Corporation, jER828) 30 Silane coupling agent (Shin-Etsu Chemical Co., Ltd., KBM-403) 2 Thermal cationic polymerization initiator (Sanxin Chemical Industry Co., Ltd., SI-60L) 3 second insulating resin layer Phenoxy resin (Nippon Steel & Sumitomo Metal Chemical Co., Ltd. YP-50) 40 Silica filler (Japan Aerosil Co., Ltd., Aerosil R805) 5 Liquid epoxy resin (Mitsubishi Chemical Corporation, jER828) 50 Silane coupling agent (Shin-Etsu Chemical Co., Ltd., KBM-403) 2 Thermal cationic polymerization initiator (Sanxin Chemical Industry Co., Ltd., SI-60L) 3

(2) Evaluation of anisotropic conductive films The anisotropic conductive films of Examples and Comparative Examples produced in (1) were cut out to an area sufficient for connection, and a connection structure of electronic components was produced using the obtained ones, and (a) capturing efficiency was evaluated as follows , (b) indentation, (c) particle flattening rate, (d) resistance value. The results are shown in Table 2.

(a) Capture efficiency For the evaluation IC and the terminal pattern shown below and the glass substrate (Ti/Al wiring) corresponding to the evaluation IC, the pressure was applied at 200° C. for 5 seconds with the pressure described in Table 2 through the anisotropic conductive film. After heating and pressurizing, a connection structure for evaluation was obtained.

IC for evaluation: Outline 1.8×20.0 mm Thickness 0.5 mm Bump size 30×85 μm, distance between bumps 20 μm, surface material of bumps Au

About 100 pairs of terminals after heating and pressing, the number of captured high-hardness conductive particles and low-hardness conductive particles was measured, and the average value was obtained. In addition, the theoretical values of the high-hardness conductive particles and the low-hardness conductive particles that existed on the terminals before heating and pressing were calculated in advance according to [100 terminals of the terminal area] × [number density of conductive particles], and the measured conductivity was obtained. The ratio of the number of particles captured to the theoretical value was evaluated based on the following criteria. In practical use, the B evaluation or more is preferable.

Capture Efficiency Evaluation Criteria A: More than 30% B: More than 15% and less than 30% C: less than 15%

(b) Indentation The indentations of the high-hardness conductive particles and the low-hardness conductive particles of the connecting structure for evaluation produced in (a) were observed with a metal microscope, and the image analysis software WinROOF (Mitani Shoji Co., Ltd.) was used for the five terminal pairs after heating and pressing. Co., Ltd.) measured the number of indentations (captures) of the high-hardness conductive particles and the low-hardness conductive particles, and obtained the average value. In addition, the theoretical values of the high-hardness conductive particles and the low-hardness conductive particles that existed on the terminals before heating and pressing were calculated in advance according to [terminal area of 5 terminals] × [number density of conductive particles], and the measured conductivity was obtained. The ratio of the number of indentations (captures) of particles to the theoretical value was evaluated according to the following criteria. In addition, with regard to the confirmed indentations, in the dispersion-type anisotropic conductive film in which the conductive particles are randomly arranged, the total number of indentations of five bumps is about 100, and the conductive particles described below are square. In the lattice-arranged neatly-arranged anisotropic conductive film, the total number of indentations of five bumps is about 200.

Indentation Evaluation Criteria OK: More than 50% of the theoretical value can be identified as indentation NG: The case where less than 50% of the theoretical value can be identified as indentation

(c) Particle Flattening Rate Immediately after production (initial stage) of the connection structure for evaluation produced in (a), and placing the connection structure for evaluation produced in (a) in a constant temperature bath with a temperature of 85°C and a humidity of 85%RH for 500 After one hour (500 hours), the distance between the opposing terminals was measured as the particle size after crimping, and the average particle size was obtained. On the other hand, the average particle diameter before crimping was also obtained in advance, the particle crushing ratio was calculated according to the following formula, and the evaluation was performed according to the following criteria. In practical use, the B evaluation or more is preferable.

Particle Flattening Rate (%) =([average particle size before crimping]-[average particle size after crimping])×100/[average particle size before crimping]

Particle Flattening Rate Evaluation Criteria at the Initial Stage and at 500 h A: More than 10% B: More than 5% and less than 10% C: less than 5%

(d) Resistance value Immediately after production (initial stage) of the connection structure for evaluation produced in (a), and placing the connection structure for evaluation produced in (a) in a constant temperature bath with a temperature of 85°C and a humidity of 85%RH for 500 After one hour (500 hours), the on-resistance was measured by the four-terminal method, and the evaluation was performed according to the following criteria. In practical use, the resistance value is preferably equal to or higher than the B evaluation.

Initial resistance value evaluation standard A: Less than 3 Ω B: 3 Ω or more and less than 5 Ω C: 5 Ω or more and less than 10 Ω D: 10 Ω or more

Evaluation standard of resistance value at 500 h A: Less than 3 Ω B: 3 Ω or more and less than 5 Ω C: 5 Ω or more and less than 10 Ω D: 10 Ω or more

Examples 5 to 8 and Comparative Examples 3 and 4 The same conductive particles as in Example 1 were prepared. Among them, by adjusting the 20% compressive elasticity modulus of the resin core particles, and preparing conductive particles (average particle size 3 μm) with a 20% compressive elasticity rate of 14,000 N/mm ² as high-hardness conductive particles, preparing a 20% compressive elasticity rate Conductive particles (average particle size 3 μm) of 6000 N/mm ² were used as low-hardness conductive particles.

The high-hardness conductive particles and the low-hardness conductive particles were mixed into the resin composition for forming an insulating resin layer (high-viscosity resin layer) in the ratio shown in Table 3, except that the same procedure as in Example 1 was carried out. In this way, an anisotropic conductive film in which high-hardness conductive particles and low-hardness conductive particles are randomly dispersed is produced.

In addition, in the same manner as in Example 1, (a) capturing efficiency, (b) indentation, (c) particle flattening ratio, and (d) resistance value were evaluated. The results are shown in Table 3.

Examples 9 to 12, Comparative Example 5 The same conductive particles as in Example 1 were prepared. Among them, by adjusting the 20% compressive elastic modulus of the resin core particles, and preparing conductive particles (average particle size 3 μm) with a 20% compressive elastic modulus of 9000 N/mm ² as high-hardness conductive particles, preparing a 20% compressive elastic modulus Conductive particles (average particle size 3 μm) of 6000 N/mm ² were used as low-hardness conductive particles.

The high-hardness conductive particles and the low-hardness conductive particles were mixed into the resin composition for forming an insulating resin layer (high-viscosity resin layer) at the ratio shown in Table 4, except that the same procedure as in Example 1 was carried out. In this way, an anisotropic conductive film in which high-hardness conductive particles and low-hardness conductive particles are randomly dispersed is produced.

In addition, in the same manner as in Example 1, (a) capturing efficiency, (b) indentation, (c) particle flattening ratio, and (d) resistance value were evaluated. The results are shown in Table 4.

Examples 13 to 16, Comparative Examples 6 and 7 With the blend composition shown in Table 1, a resin composition for forming an insulating resin layer forming a conductive particle dispersion layer was prepared, and it was coated on a PET film with a film thickness of 50 μm using a bar coater, and the temperature was 80°C. After drying in an oven for 5 minutes, an insulating resin layer was formed on the PET film. The insulating resin layer had a thickness of 6 μm. In addition, a resin composition for forming a second insulating resin layer was prepared with the composition shown in Table 1, and a resin layer having a thickness of 12 μm was formed in the same manner.

In addition, as in Example 1, high-hardness conductive particles with a 20% compressive elastic modulus of 22,000 N/mm ² and low-hardness conductive particles with a 20% compressive elastic modulus of 6,000 N/mm ² were prepared.

On the other hand, by making a mold such that the conductive particles are arranged in a square lattice as shown in FIG. 1A and the overall number density of the high-hardness conductive particles and the low-hardness conductive particles becomes the values shown in Table 5, it is known that The particles of the transparent resin flow into the mold in a molten state, and are cooled and solidified to form a resin mold with the concave portion in the arrangement pattern shown in FIG. 1A .

By mixing high-hardness conductive particles and low-hardness conductive particles in a ratio shown in Table 5 and filling them into the concave portion of the resin mold, covering the above-mentioned insulating resin layer, pressing at 60°C at 0.5 MPa to make it fit. Next, the insulating resin layer was peeled off from the mold, and the conductive particles on the insulating resin layer were pressed into the insulating resin layer under (pressing conditions: 60-70° C., 0.5 MPa) to form a conductive particle-dispersed layer. In this case, the burying rate was set to 99.9%. On the surface of the conductive particle dispersion layer in which the conductive particles are embedded, a resin layer formed of the resin composition for forming the second insulating resin layer is laminated to produce high-hardness conductive particles and low-hardness conductive particles arranged in a square lattice as a whole The anisotropic conductive film.

The thus-obtained anisotropic conductive film was cut out to an area sufficient for connection, and using the cut anisotropic conductive film, a connection structure for evaluation was produced in the same manner as in Example 1, and (a) capture efficiency was evaluated. , (b) indentation, (c) particle flattening rate, (d) resistance value. The results are shown in Table 5.

Examples 17 to 20 and Comparative Examples 8 and 9 were prepared as high hardness conductive particles with 20% compressive elastic modulus of 14000 N/mm ² and low hardness with 20% compressive elastic modulus of 6000 N/mm ² as in Example 5 conductive particles.

The high-hardness conductive particles and the low-hardness conductive particles were mixed in the ratio shown in Table 6 and filled into the resin mold, except that the high-hardness conductive particles and the low-hardness conductive particles were produced in the same manner as in Example 13. An anisotropic conductive film in which the particles are arranged in a square lattice as a whole.

In addition, it was cut to an area sufficient for connection in the same manner as in Example 1, and the cut-out anisotropic conductive film was used to evaluate (a) capture efficiency, (b) indentation, (c) particle flattening ratio, (d) )resistance. The results are shown in Table 6.

Examples 21 to 24, Comparative Example 10 High-hardness conductive particles with a 20% compressive elastic modulus of 9,000 N/mm ² and low-hardness conductive particles with a 20% compressive elastic modulus of 6,000 N/mm ² were prepared as in Example 9 .

The high-hardness conductive particles and the low-hardness conductive particles were mixed in the ratio shown in Table 7 and filled into the resin mold, except that the high-hardness conductive particles and the low-hardness conductive particles were produced in the same manner as in Example 13. An anisotropic conductive film in which the particles are arranged in a square lattice as a whole.

In addition, it was cut to an area sufficient for connection in the same manner as in Example 1, and the cut-out anisotropic conductive film was used to evaluate (a) capture efficiency, (b) indentation, (c) particle flattening ratio, (d) )resistance. The results are shown in Table 7.

[Table 2] Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Comparative Example 2 Configuration as a whole of conductive particles random random random random random random High hardness conductive particles K value (N/mm ² ) 22000 22000 22000 22000 22000 22000 Low hardness conductive particles K value (N/mm ² ) 6000 6000 6000 6000 6000 6000 Number density ratio (high:low) 100:0 90:10 70:30 50:50 30:70 0:100 Total number density (pieces/mm ² ) 56000 56000 56000 56000 56000 56000 Evaluation Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours pressure 90 MPa B NG B C B C B OK A B A B B OK A A A B B OK B B A B B OK A A A A B NG A A A A Pressure 120MPa B OK B B A A B OK A A A A B OK A A A A B OK A A A A B OK A A A A B NG A A A A

[table 3] Comparative Example 3 Example 5 Example 6 Example 7 Example 8 Comparative Example 4 Configuration as a whole of conductive particles random random random random random random High hardness conductive particles K value (N/mm ² ) 14000 14000 14000 14000 14000 14000 Low hardness conductive particles K value (N/mm ² ) 6000 6000 6000 6000 6000 6000 Number density ratio (high:low) 100:0 90:10 70:30 50:50 30:70 0:100 Total number density (pieces/mm ² ) 56000 56000 56000 56000 56000 56000 Evaluation Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Pressure 60MPa B NG B C B C B OK B B B B B OK A A A B B OK A A A B B OK A A A B B NG A A A B pressure 90 MPa B NG A A A A B OK A A A A B OK A A A A B OK A A A A B OK A A A A B NG A A A A Pressure 120MPa B OK A A A A B OK A A A A B OK A A A A B OK A A A A B OK A A A A B NG A A A A

[Table 4] Example 9 Example 10 Example 11 Example 12 Comparative Example 5 Configuration as a whole of conductive particles random random random random random High hardness conductive particles K value (N/mm ² ) 9000 9000 9000 9000 9000 Low hardness conductive particles K value (N/mm ² ) 6000 6000 6000 6000 6000 Number density ratio (high:low) 90:10 70:30 50:50 30:70 0:100 Total number density (pieces/mm ² ) 28000 28000 28000 28000 28000 Evaluation Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Pressure 60MPa B OK A A A A B OK A A A A B OK A A A A B OK A A A A B NG A A A B pressure 90 MPa B OK A A A A B OK A A A A B OK A A A A B OK A A A A B NG A A A A

[table 5] Comparative Example 6 Example 13 Example 14 Example 15 Example 16 Comparative Example 7 Configuration as a whole of conductive particles square lattice square lattice square lattice square lattice square lattice square lattice High hardness conductive particles K value (N/mm ² ) 22000 22000 22000 22000 22000 22000 Low hardness conductive particles K value (N/mm ² ) 6000 6000 6000 6000 6000 6000 Number density ratio (high:low) 100:0 90:10 70:30 50:50 30:70 0:100 Total number density (pieces/mm ² ) 28000 28000 28000 28000 28000 28000 Evaluation Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours pressure 90 MPa A NG B C B C A OK A B A B A OK A A A B A OK A B A B A OK A B A A A NG A A A A Pressure 120MPa A OK B B A A A OK A A A A A OK A A A A A OK A A A A A OK A A A A A NG A A A A

[Table 6] Comparative Example 8 Example 17 Example 18 Example 19 Example 20 Comparative Example 9 Configuration as a whole of conductive particles square lattice square lattice square lattice square lattice square lattice square lattice High hardness conductive particles K value (N/mm ² ) 14000 14000 14000 14000 14000 14000 Low hardness conductive particles K value (N/mm ² ) 6000 6000 6000 6000 6000 6000 Number density ratio (high:low) 100:0 90:10 70:30 50:50 30:70 0:100 Total number density (pieces/mm ² ) 28000 28000 28000 28000 28000 28000 Evaluation Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Pressure 60MPa A NG B C B C A OK B B B B A OK A B A B A OK A A A B A OK A A A B A NG A A A B pressure 90 MPa A NG A A A A A OK A A A A A OK A A A A A OK A A A A A OK A A A A A NG A A A A Pressure 120MPa A OK A A A A A OK A A A A A OK A A A A A OK A A A A A OK A A A A A NG A A A A

[Table 7] Example 21 Example 22 Example 23 Example 24 Comparative Example 10 Configuration as a whole of conductive particles square lattice square lattice square lattice square lattice square lattice High hardness conductive particles K value (N/mm ² ) 9000 9000 9000 9000 9000 Low hardness conductive particles K value (N/mm ² ) 6000 6000 6000 6000 6000 Number density ratio (high:low) 90:10 70:30 50:50 30:70 0:100 Total number density (pieces/mm ² ) 28000 28000 28000 28000 28000 Evaluation Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Capture efficiency indentation Particle Flattening Rate resistance Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Early stage 500 hours Pressure 60MPa A OK A A A A A OK A A A A A OK A A A A A OK A A A A A NG A A A B pressure 90 MPa A OK A A A A A OK A A A A A OK A A A A A OK A A A A A NG A A A A

It can be seen from Table 2 that the conductive particles are randomly arranged according to both the high-hardness conductive particles with 20% compressive elastic modulus of 22000 N/mm ² and the low-hardness conductive particles with 20% compressive elastic modulus of 6000 N/mm ² . For the anisotropic conductive films of Examples 1 to 4, the evaluation of indentation was good, and the conduction characteristics (initial resistance value, 500 h resistance value) were also good. On the other hand, the anisotropic conductive film of Comparative Example 1 containing only 20% of high-hardness conductive particles with a compressive elastic modulus of ^22,000 N/mm ² and a low The anisotropic conductive film of Comparative Example 2 containing the hardness conductive particles was inferior in indentation evaluation, and the anisotropic conductive film of Comparative Example 1 containing only high-hardness conductive particles had poor conduction characteristics (500 h). From this, it is inferred that if the conductive particles are only low-hardness conductive particles, the hardness is insufficient, so that it is difficult to see the indentation. In addition, if the conductive particles are only high-hardness conductive particles, the conductive particles are too hard to compress the conductive particles. Sufficient, so it is difficult to see the indentation. In addition, even in the case where the evaluation of the indentation was OK in the case of only the high-hardness conductive particles, the indentation was more easily observed in the Examples in which the high-hardness conductive particles and the low-hardness conductive particles were mixed.

It can be seen from Table 5 that the conductive particles contain both high hardness conductive particles with 20% compressive elastic modulus of 22000 N/mm ² and low hardness conductive particles with 20% compressive elastic modulus of 6000 N/mm ² , and the conductive particles are arranged in a square lattice In Examples 13 to 16, as in Examples 1 to 4 described above, the evaluation of the indentation was good, and the conduction characteristics (initial resistance value, 500 h resistance value) were also good. In Comparative Examples 6 and 7 containing only either the high-hardness conductive particles or the low-hardness conductive particles, there was a problem with the indentation.

As can be seen from Table 3, regarding both the high-hardness conductive particles with 20% compressive elastic modulus of 14,000 N/mm ² and the low-hardness conductive particles with 20% compressive elastic modulus of 6,000 N/mm ² , the conductive particles are randomly arranged. For the anisotropic conductive films of Examples 5 to 8, the evaluation of indentation was good, and the conduction characteristics (initial resistance value, 500 h resistance value) were also good. In particular, it is good even when the pressure at the time of anisotropic conductive connection is a low pressure of 60 MPa. On the other hand, the indentation evaluation of the anisotropic conductive film of Comparative Example 3 containing only 20% of high-hardness conductive particles with a compressive elastic modulus of 14,000 N/mm ² was poor, and the pressure during anisotropic conductive connection was 60 MPa, the conduction characteristics (500 h) are also poor. In addition, the anisotropic conductive film of Comparative Example 4 containing only low-hardness conductive particles as conductive particles had a problem in indentation.

It can be seen from Table 6 that the conductive particles contain both high-hardness conductive particles with 20% compressive elastic modulus of 14000 N/mm ² and 20% of low-hardness conductive particles with compressive elastic modulus of 6000 N/mm ² , and the conductive particles are arranged in a square lattice. In Examples 17 to 20, the evaluation of the indentation was good, and the conduction characteristics (initial resistance value, 500 h resistance value) were also good in the same manner as in the above-mentioned Examples 5 to 8. In Comparative Examples 8 and 9 containing only either the high-hardness conductive particles or the low-hardness conductive particles, there was a problem with the indentation.

It can also be seen from Table 4 that the examples 9 to 12 contain both the high-hardness conductive particles with 20% compressive elastic modulus of 9000 N/mm ² and the low-hardness conductive particles with 20% compressive elastic modulus of 6000 N/mm ² . For the anisotropic conductive film, the evaluation of indentation was good, and the conduction characteristics (initial resistance value, 500 h resistance value) were also good, especially even when the pressure during the anisotropic conductive connection was a low pressure of 60 MPa. In addition, the anisotropic conductive film of Comparative Example 5 containing only low-hardness conductive particles as conductive particles had a problem in indentation.

It can be seen from Table 7 that the conductive particles contain both high-hardness conductive particles with 20% compressive elasticity of 9000 N/mm ² and 20% of low-hardness conductive particles with compressive elasticity of 6000 N/mm ² , and the conductive particles are arranged in a square lattice. In Examples 21 to 24, as in Examples 9 to 12 described above, the evaluation of indentation was good, and the conduction characteristics (initial resistance value, 500 h resistance value) were also good, especially even when anisotropic conductive connection was performed It is also good when the pressure is as low as 60 MPa. In addition, the anisotropic conductive film of Comparative Example 10 containing only low-hardness conductive particles as conductive particles had a problem in indentation.

1A: High hardness conductive particles 1B: Low hardness conductive particles 2: Insulating resin layer 2b: Sag (tilted) 2c: Sag (undulation) 3: Conductive particle dispersion layer 4: Second insulating resin layer 10A, 10B, 10C, 10D, 10E, 10F, 10G: Anisotropic conductive film D: Average particle size of conductive particles La: Layer thickness of insulating resin layer Lb: The distance between the tangent plane of the central part of the adjacent conductive particles and the deepest part of the conductive particles Lc: The diameter of the exposed (right above) portion of the conductive particle in the slope or undulation Ld: the maximum diameter of the inclination or undulation of the insulating resin layer around or just above the conductive particles Le: Maximum depth of inclination in the insulating resin layer around the conductive particles Lf: Maximum depth of undulations in the insulating resin layer just above the conductive particles

1A is a plan view showing an arrangement of conductive particles in an anisotropic conductive film 10A according to an embodiment of the present invention. 1B is a cross-sectional view of the anisotropic conductive film 10A of the embodiment. 2A is a plan view showing the arrangement of conductive particles in the anisotropic conductive film 10B according to an embodiment of the present invention. 2B is a cross-sectional view of the anisotropic conductive film 10B of the embodiment. FIG. 3 is a cross-sectional view of the anisotropic conductive film 10C of the embodiment. FIG. 4 is a cross-sectional view of the anisotropic conductive film 10D of the embodiment. FIG. 5 is a cross-sectional view of the anisotropic conductive film 10E of the embodiment. FIG. 6 is a cross-sectional view of the anisotropic conductive film 10F of the embodiment. FIG. 7 is a cross-sectional view of the anisotropic conductive film 10G of the embodiment. FIG. 8 is a cross-sectional view of the anisotropic conductive film 100A of the embodiment. FIG. 9 is a cross-sectional view of the anisotropic conductive film 100B of the embodiment. 10A is a cross-sectional view of an anisotropic conductive film 100C of an embodiment. 10B is a cross-sectional view of the anisotropic conductive film 100C' of the embodiment. FIG. 11 is a cross-sectional view of the anisotropic conductive film 100D of the embodiment. 12 is a cross-sectional view of the anisotropic conductive film 100E of the embodiment. 13 is a cross-sectional view of the anisotropic conductive film 100F of the embodiment. 14 is a cross-sectional view of the anisotropic conductive film 100G of the embodiment. 15 is a cross-sectional view of an anisotropic conductive film 100X for comparison.

1A: High hardness conductive particles

1B: Low hardness conductive particles

2: Insulating resin layer

10A: Anisotropic Conductive Film

20: Terminal

A: Lattice axis

θ: angle

Claims (17)

An anisotropic conductive film, which is dispersed in an insulating resin layer with high-hardness conductive particles with a 20% compressive elastic modulus of 8000-28000 N/mm ² as conductive particles and a 20% compressive elastic modulus lower than the high-hardness conductive particles The particles are low-hardness conductive particles, and the average particle size of the conductive particles as a whole is less than 10 μm, the number density of the low-hardness conductive particles is more than 10% of the total conductive particles, and the positions of the conductive particles in the film thickness direction are aligned, including high hardness The conductive particles of the conductive particles and the low-hardness conductive particles are regularly arranged in plan view, and the surface of the insulating resin layer near the high-hardness conductive particles and the low-hardness conductive particles is opposed to the insulating resin in the center portion between the adjacent conductive particles The tangent planes of the layers have slopes or undulations. The anisotropic conductive film of claim 1, wherein the number density of the entire conductive particles is 6,000 pieces/mm ² or more and 42,000 pieces/mm ² or less. The anisotropic conductive film of claim 1 or 2, wherein the ratio (La/D) of the layer thickness La of the insulating resin layer to the average particle diameter D of the entire conductive particle is 0.3 or more. The anisotropic conductive film of claim 1 or 2 of the scope of the application, wherein the embedded rate of the conductive particles is 30% or more and 105% or less. An anisotropic conductive film, which is dispersed in an insulating resin layer with high-hardness conductive particles with a 20% compressive elastic modulus of 8000-28000 N/mm ² as conductive particles and a 20% compressive elastic modulus lower than the high-hardness conductive particles The particles are low-hardness conductive particles, and the average particle diameter of the entire conductive particles is 10 μm or more, the number density of the entire conductive particles is 20/ ^mm2 or more and 2000/ ^mm2 or less, and the number density of low-hardness conductive particles More than 10% of the entire conductive particles, the positions of the conductive particles in the film thickness direction are aligned, the conductive particles including the high-hardness conductive particles and the low-hardness conductive particles are regularly arranged in a plan view, and the high-hardness conductive particles and the low-hardness conductive particles are arranged regularly. The surface of the insulating resin layer in the vicinity has inclination or undulation with respect to the tangent plane of the insulating resin layer in the central part between adjacent conductive particles. The anisotropic conductive film of claim 5, wherein the ratio (La/D) of the layer thickness La of the insulating resin layer to the average particle diameter D of the entire conductive particle is 3.5 or less. The anisotropic conductive film of claim 5 or 6 of the scope of the application, wherein the embedded rate of the conductive particles is 30% or more and 105% or less. For the anisotropic conductive film according to any one of the claims 1, 2, 5 and 6 of the scope of application, wherein the 20% compressive elastic modulus of the low-hardness conductive particles is 10% of the 20% compressive elastic modulus of the high-hardness conductive particles Above and below 70%. The anisotropic conductive film according to any one of claims 1, 2, 5, and 6 of the claimed scope, wherein the number density of the low-hardness conductive particles is 20% or more and 80% or less of the entire conductive particles. The anisotropic conductive film of claim 1 or 5, wherein the conductive particles including high-hardness conductive particles and low-hardness conductive particles exist without contacting each other in a number ratio of 95% or more. The anisotropic conductive film according to any one of claims 1, 2, 5, and 6 of the claimed scope, wherein the high-hardness conductive particles and the low-hardness conductive particles are randomly mixed. The anisotropic conductive film of claim 1 or 5, wherein, in the above-mentioned inclination, the surface of the insulating resin layer around the high-hardness conductive particles and the low-hardness conductive particles is defective with respect to the above-mentioned tangent plane; In the above-mentioned undulations, when the resin amount of the insulating resin layer directly above the high-hardness conductive particles and the low-hardness conductive particles is higher than the surface of the insulating resin layer directly above the high-hardness conductive particles and the low-hardness conductive particles is located in the tangent plane. few. A connection structure which anisotropically conductively connects a first electronic component and a second electronic component using the anisotropic conductive film of any one of claims 1 to 12. The connection structure according to claim 13, wherein the first electronic component has a terminal formed on a PET base material. A method of manufacturing a connection structure, which uses the anisotropic conductive film of any one of claims 1 to 12 of the patent application scope to perform anisotropic conductive connection between a first electronic component and a second electronic component. The method for producing a connection structure according to claim 15, wherein, in the first electronic component, a terminal is formed on a PET base material. A roll body, which is a roll body obtained by winding the elongated body of the anisotropic conductive film according to any one of claims 1 to 12 of the patent application scope into a core.

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